<template>
    <el-breadcrumb separator="/" class="f-breadcrumb">
      <transition-group name="breadcrumb">
        <el-breadcrumb-item v-for="(item,index) in levelList" :key="item.path">
          <span v-if="item.redirect==='noRedirect'||index==levelList.length-1" >{{ item.meta.title }}</span>
          <a v-else @click.prevent="handleLink(item)">{{ item.meta.title }}</a>
        </el-breadcrumb-item>
      </transition-group>
    </el-breadcrumb>
</template>
<script>
import * as pathToRegexp from 'path-to-regexp'
export default {
  name: 'FBreadcrumb',
  data () {
    return {
      levelList: null
    }
  },
  props: {},
  watch: {
    $route (route) {
      // if you go to the redirect page, do not update the breadcrumbs
      this.getBreadcrumb()
    }
  },
  created () {
    this.getBreadcrumb()
  },
  methods: {
    getBreadcrumb (e) {
      let matched = this.$route.matched.filter(item => item.meta && item.meta.title)
      const first = matched[0]

      if (!this.isDashboard(first)) {
        matched = [{path: '/index/index', redirect: '/index/index', meta: { title: '首页' }}].concat(matched)
      }

      this.levelList = matched.filter(item => item.meta && item.meta.title && item.meta.breadcrumb !== false)

      // //$route.matched一个数组 包含当前路由的所有嵌套路径片段的路由记录
      // let matched = this.$route.matched.filter(item => item.name)
      // this.levelList = matched
    },
    isDashboard (route) {
      const name = route && route.name
      if (!name) {
        return false
      }
      return name.trim().toLocaleLowerCase() === 'index'.toLocaleLowerCase()
    },
    pathCompile (path) {
      // To solve this problem https://github.com/PanJiaChen/vue-element-admin/issues/561
      const { params } = this.$route
      var toPath = pathToRegexp.compile(path)
      return toPath(params)
    },
    handleLink (item) {
      const { redirect, path } = item
      if (redirect) {
        this.$router.push(redirect)
        return
      }
      this.$router.push(this.pathCompile(path))
    }
  }
}
</script>

<style scoped>
  .f-breadcrumb{
    margin-left: 30px;
    line-height: 30px;
    height: 100%;
    position: relative;
    display: inline-block;
  }
  /* breadcrumb transition */
  .breadcrumb-enter-active,
  .breadcrumb-leave-active {
    transition: all .5s;
  }

  .breadcrumb-enter,
  .breadcrumb-leave-active {
    opacity: 0;
    transform: translateX(20px);
  }

  .breadcrumb-move {
    transition: all .5s;
  }

  .breadcrumb-leave-active {
    float: left;
  }
</style>
